Timothy syndrome type 1 (TS1 or TS) is a severe genetic disorder with significant morbidity and mortality8–11 caused by the heterozygous c.1216G>A pathogenic variant in exon 8A of CACNA1C, resulting in a p.G406R missense variant in the α1 subunit of the L-type voltage-gated calcium channel CaV1.2 (ref. 8). This evidence concerns the gene CACNA1C and Timothy syndrome type 1.